3rd landmark Pa. forest hit by invasive pest

PITTSBURGH -- Invasive insects have been found in a third landmark Pennsylvania forest, and scientists are considering a possible link to global warming.

The U.S. Forest Service reported that the hemlock woolly adelgid has been discovered in the Tionesta forest near the New York border.

Experts said the insect is often deadly to hemlocks, and the loss of those trees can lead to a cascade of environmental changes for some wildlife, fish and plants that need the cool, deep shade that the old growth trees provide.

Forest Service silviculturist Andrea Hille said the Tionesta area of the Allegheny National Forest is one of the last remaining areas of uncut hemlock-beech forest in the Allegheny Plateau region.

Hille and other scientists said they cannot conclusively link the adelgid problem to just change in climate, but it is a concern.

The insects appeared in Virginia in the 1950s and in southeastern Pennsylvania in 1969 and have since spread to the warmer parts of many states. But now they're increasingly moving to areas that were once known for bitterly cold winters, including Tionesta.